1. Field of the Invention
This invention relates to a toner supplying device, a toner container therefor, and an image forming apparatus using the same toner supplying device and toner container.
2. Discussion of the Background
In image forming apparatuses using electrophotography, such as copying apparatuses, facsimile apparatuses and printers, a latent image of image information is formed on a surface of a drum or belt-like shaped image bearing member by first uniformly charging the surface of the image bearing member and then exposing the charged surface with light modulated with the image information. The latent image is then developed by toner, and the developed toner image is transferred onto a recording medium such as a sheet of paper directly or via an intermediate transfer member, thereby an image is formed on the sheet of paper. The image forming apparatuses of this type include a developing device for developing the latent image by toner, and generally include a toner supplying device for supplying toner to the developing device as the developing device consumes the toner as a result of developing images.
A toner container that contains toner therein is attached to the toner supplying device. Once the toner contained in the toner container attached to the toner supplying device is consumed by having been supplied to the developing device, the image forming apparatus generally stops the image forming operation and displays a message indicating that the toner container has run out of toner. The apparatus returns to an operable state once the toner container whose toner is used up is replaced with a new toner container containing toner therein and the toner is supplied to the developing device.
As related art, Japanese Patent Laid Open Publication 7-219329 describes a device in which a toner supplying device is placed apart from a developing device and connected with the developing device via a toner delivery device which delivers toner while mixing the toner with air. In the device, the capacity of a toner container for containing toner therein is made large so as to reduce the frequency of replacing the toner container and reduce the burden on a user who is unfamiliar with handling the toner container.
Japanese Patent Laid Open Publications 4-80779 and 8-137227 describes a toner supplying device including a toner container accommodating device in which a plurality of toner containers can be attached. Toner discharged from each of the plurality of toner containers is merged with each other and conveyed to the developing device. Each of the plurality of toner containers is individually attachable to and detachable from the toner supplying device and the size of the toner container is made such that the container is easy to be handled, such that the toner container can be replaced with a new toner container without stopping the operation of the apparatus.
Japanese Patent Laid Open Publication 8-137227 further describes that the toner container accommodating device accommodates two toner containers and when a sensor detects non-existence of toner in a toner conveying pipe to a developing device, an agitator of one of the two toner containers, which has not been operated, is started to be rotated to supply toner therefrom.
Japanese Patent Laid Open Publication 2-277083 describes a toner supplying device having a plurality of toner containers, which are disposed near a developing device. The toner container chosen to supply toner to the developing device is changed by rotating the toner supplying device.
Further, the present inventors have proposed a toner supplying device which includes a plurality of toner containers. The device is disposed in a position apart from a developing device and toner is conveyed to the developing device from the toner supplying device via a toner conveying device connecting the developing device and the toner supplying device.
In toner supplying devices including a plurality of toner containers as discussed above, a reserve toner container is not used until toner in a dispensing toner container is exhausted and the reserve toner container is repositioned so as to become the dispensing toner container. Therefore, it occurs that supplying of toner from the toner supplying device to the developing device is intermittent and the image forming operation is forced to be stopped when the reserve toner containers are being repositioned. Also, some toner remains inside the toner container without being discharged and supplied to the developing device and the remaining toner spills when the toner container is removed from the toner supplying device for replacement.
Further, attaching and detaching a toner container to and from a toner supplying device is not easy and the operability is poor. In particular, a related toner supplying device has a problem when removing a toner container from the toner supplying device in that a portion of the toner container which extends out of the toner supplying device is small and thus is difficult to be grasped, as described below.
FIG. 60 is a schematic drawing of a toner container attaching/detaching part of the related toner supplying device and FIG. 61 is a schematic drawing of a device for releasing the toner container from being held by a toner container holder. When detaching a toner container 101 from a toner supplying device 100, the toner container 101 is released from being held by a toner container holder 102 by pushing a release lever 104a of a release device 104, which is disposed at an circumferential part of a toner container insertion inlet 107 of the toner supplying device 100, in a direction indicated by an arrow J in FIG. 60. Then, the toner container 101 can be grasped at a bottom part 101c of the container 101 and taken out from the toner supplying device 100 through a notched part provided at a housing case 108.
When attaching a new toner container 101 to the toner supplying device 100, the toner container 101 is inserted into the toner container insertion inlet 107 from a head portion of the toner container 101 where an opening portion 101a is formed. When the toner container 101 reaches a predetermined position inside the housing case 108, a stopper 102a (which has a tang formed thereon) of the toner container holder 102 engages with an engaging protrusion 101e of the toner container 101, and thereby the toner container 101 is prevented from being removed from the toner supplying device 100. Further, an end part of the toner container 101 where the opening portion 101a for discharging the toner therethrough is formed is held at a predetermined position.
FIG. 62 is a schematic drawing illustrating a state where the toner container 101 (not shown) is removed from the inside of the toner container insertion inlet 107 by pushing the release lever 104a in a direction indicated by the arrow J to open the stopper 102a in a direction indicated by an arrow L. FIG. 63 is a schematic drawing illustrating that the toner container 101 is inserted into the toner container insertion inlet 107 from the side of the opening portion 101a in a direction indicated by the arrow J and the stopper 102a of the toner container holder 102 engages with the engaging protrusion 101e of the toner container 101, such that the toner container 101 is held at the predetermined position inside the housing case 108 in a state that prevents the toner container from being removed from the toner supplying device 100. A cap 101g is a device to open/close the opening portion 101 such that opening/closing the opening portion 101a with the cap 101g is accomplished by an operation of an open/close device 103 when the toner container 101 is held at the predetermined position inside the toner insertion inlet 107 as described above. In this state, because the head part of the toner container 101 pushes a slider 103a of the open/close device 103 in the direction J, a gap d1 is formed between an end part of the holder 102b of the toner container holder 102 and an end part of the slider 103a. By thus forming the gap d1 between the end part of the holder 102b and the end part of the slider 103a, it becomes possible to completely close the opening portion 101a of the toner container 101 with the cap 101g.
FIGS. 64-69 are sectional drawings illustrating an open/close operation of the opening portion 101a with the cap 101g. In FIG. 64, when a chuck 103b of the open/close device 103 is moved in a direction P by a motor (not shown), because a spring 103c is pushing the slider 103a in a direction K, only the chuck 103b moves in the direction P relative to the slider 103a to change the relative position between them, and due to an operation of a small-diameter portion 103a1, a tip end 103b1 of the chuck 103b is closed so as to grasp a protrusion 101g1 of the cap 101g. The spring 103c is a device to restrict the slider 103a to move in a direction opposite to the direction K and the slider 103a is a device to control opening/closing of the tip end 103b1 of the chuck 103b. In FIGS. 65 and 66, when the chuck 103b is moved in the direction P, the cap 101g can be detached from the opening portion 101a of the toner container 101. The slider 103a stops moving when an end of the slider 103a strikes a holder housing case 102c. The slider 103a may be stopped when a predetermined period of time, which is sufficiently long for detaching the cap 101g from the opening portion 101a, is elapsed, when a predetermined current is detected at a driving motor (not shown), or when the slider 103a is detected by a sensor (not shown) at a predetermined position. In a state that the cap 101g is detached from the opening portion 101a, as shown in FIGS. 67 and 68, when the chuck 103b is moved in a direction Q by a driving motor (not shown) until a gap d2 between the slider 103a and the chuck 103b disappears, due to friction between the opening portion 101a and the cap 101g, the tip end 103b1 of the chuck 103b opens. In FIG. 69, when the chuck 103b is further moved in the direction Q, the opening portion 101a of the toner container 101 can be completely closed by the cap 101g. For completely closing the opening portion 101a by the cap 101g, the gap d1 is formed between the right side end of the holder 102b and an engaging part 103A (FIG. 68) of the chuck 103b such that the engaging part 103A does not interfere with the right side end of the holder 102b. In this state, when the release lever 104a of the release device 104 is pushed in the direction J, because a tip end of the release lever 104a contacts a tapered surface of the stopper 102a, the stopper 102a is disengaged from the engaging protrusion 101e of the toner container 101, and thereby the toner container 101 becomes detachable from the toner supplying device 100. The toner container 101 is moved by a pressing force of the spring 103c in a direction R, such that the bottom part of the toner container 101 comes out of the toner container insertion inlet 107 by the distance d1.
For enhancing easiness of taking out the toner container 101 from the toner supplying device 100 by grasping the bottom part of the toner container 101, it is desirable to increase the distance that the bottom part of the toner container 101 comes out of the toner supplying device 100. However, if the gap d1 is made wider, the positional relation between the slider 103a and the chuck 103b changes and causes that the chuck 103b to move left before the slider 103a moves. Therefore, when the chuck 103b is moved to the extent to enable the toner container 101 can be detached from the toner supplying device 100 as shown in FIG. 69, the tip end 103b1 of the chuck 103b is closed to grasp the cap 101 g, causing a problem that the cap 101g is detached from the toner container 101 being in a state to be removed from the toner supplying device 100. When the toner container 101 is removed from the toner supplying device 100, the toner remaining inside the toner container 101 spills out.
Accordingly, for avoiding the above problem, as presently recognized, the distance d1 needs to be restricted to within a predetermined limitation so as to not cause the above problem, and as a result, the distance the toner container 101 comes out of the housing case 108 becomes short. This makes difficult to grasp the toner container 101 for removing the container 101 from the toner supplying device 100. Further, because the distance the toner container 101 comes out of the housing case 108 is short, it is not easy to recognize that the toner container 101 is in a released state. Therefore, when the toner container 101 is not released from the held state by pushing the release lever 104a and if the release lever 104 is let go, the stopper 102a engages with the engaging protrusion 101e again, and than the toner container 101 can not be removed from the toner supplying device 100. Further, handling of the toner container 101 for replacement is not so easy because the engaging protrusion 101e of the toner container 101 is easily hooked to other members of the toner supplying device 100 when removing the toner container 101 from the toner supplying device 100.
Furthermore, generally, handling of a toner container for a toner supplying device is poor not only in attaching to and detaching from the toner supplying device but also in transportation. Sometimes, the user drops the toner container or the toner container tumbles by itself. When the toner container is large, these problems becomes significant. Also, when a toner container has been stored in a standing condition for some time, because the toner contained inside the container is put to one side, it occurs that the toner is not conveyed out of the container smoothly, causing insufficient amount of toner supplied to a developing device and thereby causing a decrease of an image quality.